Single neutron star merger supplied half the solar system’s plutonium

We are all, as Carl Sagan said, star dust. You might think that
since most stars are pretty much the same, all star dust is equal.
But we have evidence than some star dust is
more equal than others. Yes, some elements seem to have a very
special origin: neutron star
mergers.

Most stars are pretty much all hydrogen. Near their center,
fusion busily turns hydrogen into helium. Eventually, that hydrogen
will run out and, like a pub that runs out of beer, the real
destruction begins. The star starts turning helium into heavier
elements at an increasingly feverish rate. The end, no matter how
hot and heavy the star, comes when the star’s core is made of
iron.

Up to iron, the process of fusion releases more energy than it
consumes. But after iron, fusion consumes more energy than it
releases, which essentially shuts the star down. Once this was
understood, scientists were left wondering where the remaining 80
odd elements that are heavier than iron came from.